Samma-vayama (right exertion, right effort) is in the concentration group of the noble eightfold path, consisting of 'samma-vayama', 'samma-sati' and 'samma-samaadhi'. Another name of samma-vayama is 'sammappadhaana'. What does sammappadhaana mean?

Because sammappadhaana is exactly the same as samma-vayama, which is in the concentration group of noble path-factors, that maybe why it is called the four "rightful concentrations of the mind" in the Padhaana Sutta:

"Bhikkhus, these four are the rightful concentrations of the mind. What four?

"Here, bhikkhus, the bhikkhu arouses interest and effort and strives to pursue the mind, for the non-arising of not arisen demeritorious thoughts, for the dispelling of arisen demeritorious thoughts, for the arising of not arisen meritorious thoughts and the unconfused establishment, development and completion of arisen meritorious thoughts.